Holy Ghost is a Revelator

Joseph Smith

No man can receive the Holy Ghost without receiving revelations. The Holy Ghost is a revelator. (Teachings of the Prophet Joseph Smith, p.328)

Joseph Fielding Smith

His mission is to teach us all truth. He partakes of the things of the Father and the Son and reveals them to those who serve the Lord in faithfulness. (Doctrines of Salvation, 1:38)